Chemistry yields DNA fossils

One way to make things at the molecular
scale is to use DNA, which can be coaxed to self-assemble into various
structures. The trick is getting other useful materials like inorganics
into the mix.

Researchers from Kyushu University in Japan have used bacterial
DNA as a matrix for making structures from silicates, which are materials
like glass and concrete that contain silicon.

The technique could be used to make nanoscale containers, wires,
patterns, and chemical catalysts.

DNA and silicate materials are both negatively charged, meaning
the two ordinarily repel each other rather than stick together. At the
same time, DNA is only soluble in water, but silicates are soluble in
organic solvent.

The researchers made the two compatible by adding a hydrocarbon
chain to the DNA that had positively charged groups of molecules at its
head and tail. The stronger positive charge at the head caused the hydrocarbon
chains to attach to pairs oxygen atoms on the DNA backbone, leaving the
weaker tail charge free to connect silicate particles, which then fused
together. At the same time, the combination DNA-hydrocarbon chains was
soluble in the organic solvent required for silicate.

Once the silicate is in place, the DNA is removed by heating.
What is left can be thought of as an artificial fossil in the shape of
the DNA.

The work appeared in the June 16, 2004 issue of Angewandte
Chemie International Edition.